1. Field of the Invention
The present invention relates to a circuit board of semiconductor package and a method for fabricating the same.
2. Description of Related Art
In current semiconductor packaging technology, chip carriers are commonly used for the interconnection between integrated circuit (IC or chip) and the next-leveled electronic components, such as mother boards, module boards or the like. Circuit boards are generally used in the chip carriers with high I/O count. A conventional circuit board is mainly composed of a plurality of patterned conductive layers and a plurality of dielectric layers alternately stacked to one another. And, the patterned conductive layers are electrically connected through a plurality of conductive vias.
Flip-chip bonding process is a packaging process applied on IC having high I/O count, wherein the IC can be connected to the circuit board through a plurality of conductive bumps arranged in array. In addition, ball grid array (BGA) is another packaging process applied on circuit boards having high I/O count, wherein the circuit board can be electrically connected to the next-leveled electronic component through a plurality of conductive balls (e.g., solder balls) arranged in array.
One surface of the circuit board is disposed with bump pads for jointing the bumps and the opposite surface of the circuit broad is disposed with solder ball pads for jointing the conductive balls. The pads including the bump pads and the ball pads can be classified into two types: solder mask define (SMD) and non-solder mask define (NSMD), depending on whether the pads are covered by the solder mask or not.